A social network is a social structure made of a plurality of nodes (which generally represent individuals or organizations) that are tied by one or more specific types of interdependency, such as financial relationship, interpersonal relationship, social relationship, etc. The social network as a nature structure emerges from our daily life and it may reveal quite a lot insight from the relationships among nodes.
Therefore, social network analysis becomes one of the most important research topics since year 1964, and has now moved to be a paradigm, with its own theoretical statements, methods, social network analysis software, and researchers.
For the social network analysis, visualization is an important technology that may provide great convenience. Currently, the visualization of the social network can be categorized into two major types. The first type is such a visualization method as illustrated in a node link diagram shown in FIG. 1(a), that only presents interdependency among nodes while ignoring context information of the nodes; and the second type is such a visualization method as illustrated in FIG. 1(b), that not only presents interdependency among nodes but also presents the context information of the nodes.
In the social network analysis, an analyst's study of the social network not only focuses on the topology of the social network, but also takes context information behind each node in the social network into account.
Therefore, since the first type of visualization method of the social network does not present context information behind nodes, it suppresses the easy development of the social network analysis.
Furthermore, in the second type of visualization method of the social network, even though the context information of nodes is presented, if the presentation layout is disordered, the social network analysis will also can not be facilitated to carry out effectively. For example, it may be seen that, in the visualization method illustrated in FIG. 1 (b), an extreme visual clutter is caused due to an inappropriate presentation manner in which a variety of context information of a huge number of nodes is presented simultaneously on a single view.
Furthermore, a data set of a network is usually multi-dimensional, i.e. contains a plurality of property information. However, in the second type of visualization method, in addition to the possible case of clutter of presentation layout as shown in FIG. 1 (b), there also exists a case of compression of high-dimension (a plurality of properties) of context information to low- dimension (one or few properties) of context information. In this case, since the majority of context information of nodes is omitted, a distortion of presented contents will be caused.
These above issues not only exist in the case of visualization of the social network, but also exist in the case of visualization of other content-based networks, such as SMS (Short Message Service) network, Internet, etc.